1. Field of the Invention
The present invention relates to a flash photographing system having a camera and a flash unit.
2. Related Background Art
In a conventional flash photographing system, a charge complete signal is supplied from a flash unit to a camera when a charge voltage of a main capacitor for supplying emission energy to a discharge tube of the flash unit reaches a predetermined value.
In order to systemize combinations of flash units and cameras, automate flash photographing, and apply flash photographing in a variety of applications, in addition to the charge complete signal, flash unit control data such as maximum flash light amount is required at the camera side, and other data such as F numbers of lenses and film speeds is required at the flash unit side. Such data must be exchanged between the camera and the corresponding flash unit.